Weighted relief valve



April 1949- I c. w. ABERCROMBIE 2,467,716

WEIGHTED RELIEF VALVE Filed Jan. 24, 1947. 2 Shets-Sheet 1 INVENTOR CHARLES W. ABERCROMBIE ATTORNEYS p 1949- I c. w. ABERCROMBIE 2,467,716

WEIGHTED RELIEF VALVE Filed Jan. 24,. 1947 2 Sheets-Sheet 2 INVENTQR CHARLES .W. ABERCROMBIE MTMM/M ATTORNEYS Patented Apr. 19, 1949 2,467,716

i l 'it WEIGHTEDQRELIEF VALVE Charles W. Abe orpmbie, B1 i 1gep9rt, Conn as i n x mom. :1 P od g i ii ai orno t ene mens-k1. pp ication Janu mz' 947 seria fl 724,9,

This invention relatesto, a weighted rel thought tp an operation that might better, valve intended particularlyfor venti ligftht pres accomplished automatically. It. is the object 1 surewithin pressurecookers. macaw overcome thisishortcoming my application, Serial No, 642,526, meal tainedl this'fobje t by providing lthe January 21, 19 l 6, Ihave illustrated ahdQdsCribed eioflthe kri ob with a cam lug which azprs sure cooker: with novel pressure control thefballvalve iwhen the knob dial isset means. Thetpressurejrelief veritQrnountedlon g,' and positively rolls the bailout of the cover; isclosedbyna ste eil ball valveloi."i ni ficant weight, which, it; not held on its: seat? a tle-unlicen edei h entzea se aw le e dis a ed: t subste i la n e te es a agreement; This ball isheld on. its

ttom view of the knob. coo shown in these, drawings 'l o which is mounted a cov er is provided, just below. its rim, with 1 spaced-external; cam lugs 3 and the v ne wisgmrqwdee, on its. flange, with; a series artspe eqi internal cam lugs. 4.d esigned to t e with 'the lugls on the pot to hold the:

port or fulcrum. Thus the cook, knob, which issuitably m rked shifts the inicrum'en d vari'es the moin'nts of'the weighted knob about that; fi.il c1;urr 1;, theneby readily con-' cg? I lli 7 W ll. 33 1! his. ba l'w l h b displaced' and hence the pressure at which the food will be cooked. At one pointon the under- L e d ur ing the cooking operation; The; face of the knob the1,e .is. a depression large of;the;cover justabovethe;fiange is, enough to receiv the ball andv permit its, out; ed with anannular groove which serves ward movem ent under pressure Thus, when the knob is set so that this depr' on overlies} of t guy. presses to form a tight-scal ball; the steam within the co e is venteld at du g the cookin -l operation. 'Ifhepot"ispro v substantially. atmospheric press ,4 vi'de with ahenmm nq thecover witha handle,

This pressure controlmeans works excellently 8. qqver upon-. thepotthe cover; in actual use in the many cookers equipped with handle 8 is swung counter-clockwise to make an it. t iS j however, t One s c i angle of some with the handle 1. In this If, after the source of heat has been removed, operation the lugs 4 on the cover pass between the cook permits the steam within the cooker to the lugs 3 on the pot, and the rim of the pot lies condense before the cover is removed, a vacagainst the gasket 6. The handle 8 is then swung uum is formed which makes it impossible to open clockwise causin the lugs 4 to move below and the cooker unless the ball valve of the vent is be cammed down by the lugs 3, drawing the unseated to permit equalization of internal and gasket 6 firmly against the rim of the pot and external pressures. This can be done by insertmaking a steam-tight seal between the cover ing a knife blade between the knob and the cover and the pot. Steam pressure may also be given and rolling the ball partly out of its seat; neveraccess to the back of the gasket as shown in theless a careless and thoughtless cook may be my application Serial No. 704,226, filed October momentarily dismayed, and others compelled to 18, 1946. When the two handles are in vertical alignment the cover is properly seated on the pot.

As shown in the drawings, the cover is concave-convex, but provided, at the center of its outer face with a flat circular area 9. Near the perimeter of this area, and diametrically opposite the handle 8, is a relief vent IL terminating at its upper end in a conical valve seat l2 and at its lower end in a shallow cup defined by an annular ridge I3 cast on the cover. A steel ball valve I4 is mounted within the seat and when seated closes the vent I I. As shown best in Figure 3, this ball projects above the surface of the flat area 9. At the center of the fiat area 9 is a threaded hole l5, and extending radially from this hole along the axis of the handle 8 is an elevated groove l6. Threaded within the hole is a hollow cylindrical gudgeon or boss H terminating at its upper end in an enlarged head [8.

A pressure-setting knob I9 is loosely and rotatably journalled on and retained by the boss H, as shown best in Figure 3. This knob comprises a circular plate 2| on which is mounted a bulbous handle designed for easy manipulation. The plate of the knob is of substantially the same size as the flat area 9 and, therefore, overlies the ball l4 and the groove IS. The lower face of the knob plate is provided with five projections 22a, 22b, 22c, 22d and 22a which, as shown in Figure 4, are spaced apart by angles of 45 and each is progressively farther from the center of the knob. These projections are arranged in what may be described as a spiral. A selected one of these five projections is designed to lie Within the groove 9 and partly support the knob which overlies and is also partly supported by the ball valve I4; When the internal steam pressure balances that exerted by the weight of the knob fulcrumed on the pro-- jection lying within the groove 9, steam will escape and vent the cooker. This pressure can be varied by turning the knob selectively to place one of the projections 22 within the groove 9 and thus vary the moment arm of the knob. All of this has been described in greater detail in my application Serial No. 642,526.

In order to enable the cooker to vent at su-bstantially atmospheric pressure, the underface of the knob plate shown in my earlier application was provided with a depression large enough to receive the ball, and diametrically opposite with a sixth projection placed near the periphery of the plate. In accordance with the present invention I provide the underface of the plate 2| near its periphery with a projecting cam lug 23, and diametrically opposite with a sixth projection 24, The cam lug engages the ball [4 when the projection 24 lies within the groove 9 and the knob is at Vent and rolls it out of its conical seat l2, as shown in Figure 3, thereby positively opening the relief vent H and keeping it open. It thus becomes impossible for a vacuum to form and the cooker is rapidly and automatically vented.

There is another advantage flowing from my invention: Sometimes food particles are expelled through the vent and lodge around the ball in the ball seat so as to interfere with the escape of steam. If the ball is positively displaced during cooling, the inrush of air as the steam condenses sucks the food particles back into the cooker and clears the vent.

The boss I! is provided with an axial bore 25 which is sealed by a plug of fusible metal 28. When the pressure within the cooker reaches a predetermined point, this metal plug melts and vents the cooker thus acting as a safety valve.

I claim:

1. A weighted relief valve assembly comprising a relief valve base having a pressure relief vent, a

ball valve seated in the vent therein, a weightv loosely and rotatably mounted on the base and. overlying the valve, a plurality of projections on. the underface of the weight spaced at varying distances from its center of gravity, the weight.

being supported upon the base by the valve and one of the projections beyond the center of grav- .ity of the weight, so that the projection which is: to serve as the second support or fulcrum for the: weight can be selected by turning the weight,

and the pressure at which the valve opens thereby controlled, and a cam lug on the weight for engaging and unseating the ball to open the vent.

2. A weighted relief valve assembly comprising a relief valve base having a pressure relief vent therein, a ball valve seated in the vent, a weighted knob loosely and rotatably mounted about its center of gravity on the base adjacent the vent, overlying and partly supported by the ball, an elevated groove on the base, below the knob and on the side of the center of gravity opposite the ball, a plurality of projections on the underface of the knob spaced different distances from the center of gravity of the knob and each designed to lie, one at a time, in the groove and share the support of the knob with the ball and serve as a fulcrum for the knob, and a depending cam lug on the underface of the knob for engaging and unseating the ball to open the vent, whereby the knob may be rotated manually to place a selected projection within the groove or to unseat the ball, to vary the external pressure on the ball or to vent the valve.

CHARLES W. ABERCROMIBIE.

REFERENCES CITED The following references are of record in the .file of this patent:

UNITED STATES PATENTS Number Name Date 280,721 Culver July 3, 1883 1,464,116 Steudel Aug. 7, 1923 2,115,998 OConner May 3, 1938 2,200,903 Stephens May 14, 1940 

